Electric switch



Jan. 30, 1934. G H. WH|TT|NGHAM 1,945,459

ELECTRIC SWITCH Filed Dec. 24. 1931 2 Sheets-Sheet 2 um I T Patented Jan. 30, 1 934 NITED STATES PATENT OFFICE ELECTRIC SWITCH Application December 24, 1931 Serial No. 583,066

2 Claims.

The purpose of this invention is to provide a switch of simple construction and compact form which can be easily assembled and which is adapted to break an electric circuit at a num- 1 her of points simultaneously to thereby reduce ping mechanism fails; but of course theswitch is not limited in its use to this service.

The switch comprises a shaft, angular in cross section and mounted in standards or bearings,

,, upon a suitable base, a sleeve of insulating material, of similar cross section, surrounding the shaft and flat switch blades having openings at their central portions, fitted onto the sleeve, these blades being rotatable with the shaft and sleeve. Cylindrical blocks of insulating material, having central openings, surround the shaft on opposite sides of each blade, and these blocks have flanges on their opposing faces which meet and enclose the central portion of the blade, these flanges having registered slots through which the arms of the blade extend. At the opposite sides of the shaft, terminal clips are mounted and the arms of each blade are adapted to engage a pair of these clips in the closed position of the switch. The blocks associated with each blade are spaced from the blocks associated with an adjacent blade by suitable means, preferably an arc shield which separates the blades and their respective terminals and prevents arcing from. one blade to another or one terminal to another. As the blades are insulated from the shaft and their central portions are enclosed by the blocks referred to, there is no possibility of arcs extending from the terminals to the shaft. The various parts on the shaft are not tightly fitted and therefore the blades can adjust themselves to the terminal clips so as to make good contact therewith.

In the accompanying drawings,

Fig. 1 is a top plan view of the switch, in

closed position;

Fig. 2 is a side elevation of the same;

Fig. 3 is a detailed perspective view, on an enlarged scale, of the shaft and some of the parts through which the shaft extends;

Fig. 4 is a perspective View of one of the terminal clips and a connector;

Fig. 5 is a central vertical section through the switch mechanism, taken on the line of the shaft, the switch blades being shown in open position and the stationary members of the switch being omitted, and,

Fig. 6 is a section on the line 6-6 of Fig. 1.

The switch shown in the drawings is suitable for three-phase circuits and comprises a shaft 1 mounted in standards 2 and 3 which are secured to a suitable base of insulating material 4. This shaft carries switch blades a which are insulated from the shaft, as hereinafter described, each blade adapted to engage a pair of switch terminals b and 0, these terminals being arranged on opposite sides of the shaft. The switch is adapted to br ak the circuit at points simultaneously, reducing the arc to a minimum, and are shields d are arranged at the sides of the switch terminals to prevent possible arcing between adjacent terminals. The terminals b and c are alike, each consisting of a U-shaped clip having a flat central portion 5 adapted to rest upon the insulating base i and arms 6 which project upwardly at right angles to the central part and thence converge to frictionally engage the switch blade. A flat metal connector 7 has an offset portion 7 adapted to fit between the arms of the clip and rest on its central lower base portion 5, and a screw 8 extends through the insulating base 4 and through the parts 5 and 7 and secures the clip to the insulating base. The ends of the connectors 7 which are associated with and project beyond the clips I) are secured to the base by binding posts 9 to which the service wires be connected, and the ends of the connectors which are associated with the clips 0, and which rest on the base 4, are secured to the base by screws 10 to which the house wires or wires which lead to a motor may be connected. The holes in the base through which the screws 9 and 10 extend are large enough to permit slight lateral adjustment of the connectors, and by this adjustment, the clips, which pivot on the screws 8, may be alined so that the switch blades will engage the contact faces of the clips evenly.

The shaft 1, as shown, is square in cross section and it has a reduced end 1 circular in cross section and adapted to fit into an opening in the standard 2. The metal washer 11, having a 10 square central opening, fits on the opposite end portion of the shaft and has a hub 11 which extends into an opening 12 in the standard 3 and forms a bearing surface for the shaft in the opening. A square tube 13 of insulating material, 10 preferably a phenol condensation product, surrounds the shaft between the washer 11 and the standard 2 and a short section of similar tubing 13 encloses the part of the shaft which projects 11 outwardly beyond the standard 3. One end of the shaft is bent at right angles to the body of the shaft and is provided with a handle 14, as shown. The shaft fits easily into the tube 13 and is held in place by a screw 15, threaded into the reduced end of the shaft, and a washer 16 which bears against the standard 2. By removing the screw 15, the shaft may be withdrawn from the tube 13.

The switch blades are made of flat metal stampings and each blade has a square opening 1'7 at its central portion to receive the square tube, and the blades fit easily on the tube and are rotatable with and insulated from the shaft. Both arms of each blade are beveled, as indicated at 18, along the edges where the blades leave the stationary clips, in breaking the circuit, so that the breaks in the circuit will occur on surfaces of relatively large area. The edges of the centralportion of the blade are enlarged, forming hubs arcuate in form, as indicated at 19.

The are shields consists of rectangular pieces of refractory material, which rest edgewise on the base 4 and have enlarged central openings 20 through which the shaft extends. The switch blades are centered between the adjacent shields by cylindrical blocks e of insulating material, each block having a circular axial opening 21 through which the shaft extends and having a flange 22 on one face which is cut away at diametrically opposite points forming notches 23 to receive the arms of the switch blade. The flanges 22 are, in depth, equal to one-half the thickness of a switch blade. When the two cylindrical blocks are brought together, the flanges 22 rest upon the arcuate portions of the blade and the arms of the blade project through the recesses formed by the notches 23 of the opposing blocks. Thus the blocks are supported by the blades and the contacting ends of the blades project beyond the blocks, while the central portions of the blades are enclosed by the insulating material and also insulated from the metal shaft, and there is no possibility of arcs extending from the stationary contacts to the shaft. The cylindrical blocks may turn with freedom between the arc shields which they abut against. The are shields need not be secured to the base 4, as they are prevented from moving by the shaft which extends through them. To avoid wear of the corners of the insulating tube 13 by contact with the margins of the openings in the arc shields, bushings 20 of insulating material, such as a phenol condensation product, may be inserted in said openings.

For the purpose of facilitating making a quick break and also for holding the switch central in its open position, spring arms 24 are provided, these arms being spaced apart at their lower ends by a metal block 25 which is secured to the standard 3 by a screw 26. These spring arms bear against opposite sides of the insulating tube 13' and as the latter is square in cross section, the arms bearing against the sides of the tube will hold the shaft from turning when the switch blades are in the open position.

The blades are not gripped tightly between the cylindrical blocks or fastened to the shaft, and therefore adjust themselves to the stationary clips so as to make good contacting surfaces therewith. The blades may swing through the clips in passing from the horizontal to the vertical position in either direction of rotation of the shaft.

What I claim is:

1. An electric switch mechanism comprising a base of insulating material, bearings mounted thereon, a shaft, angular in cross-section, journaled in said bearings, a tube of insulating material, angular in cross-section, fitting over said shaft, a switch-blade having an angular opening at its central portion fitting on said tube, blocks of insulating material supported by the blade, said blocks loosely surrounding the shaft and enclosing the central portion of the blade, and terminal clips at opposite sides of the shaft adapted to be engaged by the ends of the blade.

2. An electric switch mechanism comprising a base of insulating material, bearings thereon, a shaft, angular in cross-section, journaled in the bearings, a tube of insulating material, angular in cross-section, sleeved on the shaft, switch-blades having enlarged central portions and having angular openings at said portions fitting on said tube, two similar blocks of insulating material loosely surrounding said tube and arranged at opposite sides of each blade, the opposing blocks having side flanges which fit around the enlarged central portions of the blade and meet face to face, whereby the blocks are supported by the blade and enclose the central part of the blade, said flanges having notches through which the arms of the blade extend, and pairs of terminal clips at opposite sides of the shaft, each pair adapted to be engaged by the ends of one of said blades.

GEORGE H. WHITTINGHAM. 

